If you notice any of these visible symptoms, you should bring them up to your doctor at your next appointment to get them checked out.
Hyperpigmentation and Discoloration
Sun exposure isn’t the only cause of hyperpigmentation. Thick, velvety brownish gray patches on the skin—especially around the neck, armpit, or groin—could also be an early sign of diabetes, says Raj.
Gray skin can appear for a number of reasons. One could be that oxygen isn’t getting to your blood—a possible sign of emphysema, says Kim Laudati. It could also signal an impending heart attack. Other things it could point to include pulmonary tuberculosis, pneumonia, and some cancers. A lesser-known reason for gray skin can be peritonitis—an inflammation of a thin layer of tissue inside the abdomen, which is caused by bacteria or fungus.
Eyes that turn a shade of yellow may be due to a condition known as scleral icterus, which could possibly indicate that your liver isn’t functioning properly, says dermatologist Soheil Simzar, M.D.
Eye Bags and Puffiness
High-sodium foods and a diet rich in salt can promote water retention throughout the body, including the under-eye area, says celebrity doctor Roshini Raj, M.D. Chronic allergies may also show up on the sensitive skin under your eyes—they dilate blood vessels and can cause them to leak, which creates puffiness and dark purple-blue hue.
Blue Shins or Gums
If certain parts of your skin—such as your shins or your gums—turn blue, you may be having a reaction to a medication, says Simzar. However, if your skin turns a bluish gray, this may indicate chronic ingestion of lead products.
Extreme Sensitivity to Sun
Skin that is especially sensitive to sun exposure can be a sign of the autoimmune disease lupus erythematosus, says dermatologist Dina D. Strachan, M.D.
Itchy, Blistering Rash
This can be known as dermatitis herpetiformis. It’s a sign of celiac disease when your digestive system is sensitive to gluten, says Raj. Lesions can appear anywhere but occur most often around the knees, elbows, scalp, back and buttocks, and may be preceded by an intense burning sensation.
If your skin turns orange, you may be over-consuming carrots or other vegetables rich in carotene, says Simzar.
If your skin turns bronze—not including the effects of sun bathing—this may show a hereditary disorder called hemochromatosis, says Simzar.
Excess Facial Hair
Unwanted hair in women—predominantly along the jawline, chin, and upper lip—can be a symptom of polycystic ovary syndrome, a hormone imbalance in which male hormone levels are elevated, says Raj.
Dry cracks around the mouth may indicate a deficiency of B vitamins like niacin, riboflavin, and vitamin B6. You can find niacin in canned wild tuna, riboflavin in spinach, and B6 in chickpeas, says Holthaus.
Dry Skin or Nails
If your skin becomes dry and your hair and nails become brittle, this could potentially point to a thyroid problem, says Simzar. Skin should always appear smooth, with no rashes, swelling or scales. Exceptionally dry skin may be due to a lack of sufficient vitamin A, essential fatty acids like omega-3s, or zinc, says Tori Holthaus, R.D.